1. Field of the Invention
The present invention relates to novel diamide compounds and medicines useful in preventing and treating allergic immunological diseases, comprising such a compound as an active ingredient.
2. Description of the Background
IgE, which is a kind of immunoglobulin (Ig), is an allergen-specific molecule produced by an IgE producing cell differentiated from a B cell. This process is triggered by the contact of an immunocyte with an allergen in vivo.
IgE is produced in a target organ for an allergy and binds to a receptor on the surface of a mast cell, which is a central effector cell in an allergic reaction, or a basophil (sensitized state). After the sensitization, allergic chemical mediators such as histamine, leukotrienes, prostaglandins and PAF, and injuring enzymes such as tryptase are released from the mast cell stimulated by the reaction of the specific IgE and the allergen which invades in the living body, so that immediate responses, such as vascular permeability acceleration, smooth muscle constriction, and vasodilation are elicited. Further, cytokines such as IL-4, which directly activate other immune system cells, are also secreted from the stimulated mast cell. As a result, eosinophils, basophils and the like infiltrate into a tissue, and the allergic chemical mediators and tissue injuring proteins such as MBP, which are secreted by these inflammatory cells, induce a late response, so that the allergic symptom is lingered and taken seriously ill.
From this, IgE is considered a substance fundamentally participating in the attack of an allergic immunological disease.
Therefore, several compounds having an inhibitory effect on the production of an IgE antibody have heretofore been found and reported with a view toward developing antiallergic agents [Pharmacology and Therapy, 1994, 22(3), 1369; Japanese Patent Application Laid-Open No. 106818/1989; Japanese Patent Publication No. 17506/1995; and Japanese Patent Application Laid-Open No. 92216/1996]. However, the object has been not always sufficiently achieved under the circumstances.